This invention relates to the continuous, ascending, vertical casting of a cast iron tube without the use of a core to form the hollow interior of the tube. More specifically, the invention concerns means for supplying molten metal to a tubular die defining the exterior shape of the tube, either from a syphon unit or from a gas-pressurized casting ladle.
In a known unit of this type as described in commonly assigned U.S. patent application Ser. No. 630,043 filed July 12, 1984, a tubular die having a vertical axis works together with a support stand that forms the die's base to create a crucible for molten metal brought up from below, either by a syphon unit or by a casting ladle. The crucible formed by the tubular die and the support stand contains a cylindrical volume of molten metal, the size of which increases with the diameter of the tube to be formed.
Applicants addressed the problem of considerably reducing the volume of molten iron that is to be brought to the lower end of the die in a unit designed for the continuous, ascending casting of a tube, in spite of the absence of a core, thereby realizing a substantial savings in terms of the energy needed to melt the metal.